共查询到20条相似文献,搜索用时 15 毫秒
1.
Peng Sun Yingshuo Yu Jing Xu Yanfeng Sun Jian Ma Geyu Lu Author vitae 《Sensors and actuators. B, Chemical》2011,160(1):244
The hierarchical unloaded and Pd-loaded SnO2 nanostructures, consisting of many aggregative nanorods were prepared by one-step hydrothermal method. A possible formation mechanism of these hierarchical structures was proposed. The butanone sensing properties of the sensors based on unloaded and hierarchical Pd-loaded SnO2 nanorods were investigated. The results indicate that the response of sensor using hierarchical Pd-loaded SnO2 nanorods to 1000 ppm butanone was 451 at 250 °C, which was about 10 times higher than that of sensor based on unloaded SnO2. Such enhanced gas sensing performances can be attributed to both the chemical and the electrical contribution of Pd loading. 相似文献
2.
N.M. ShaalanAuthor Vitae T. YamazakiAuthor Vitae T. KikutaAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(1):11-16
SnO2 microwires, nanowires and rice-shaped nanoparticles were synthesized by a thermal evaporation method. The diameters of microwire and nanowire were 2 μm and 50-100 nm, respectively, with approximately the same length (∼20 μm). The size of nanoparticles was about 100 nm. It was confirmed that the as-synthesized products have SnO2 crystalline rutile structure. The sensing ability of SnO2 particle and wire-like structure configured as gas sensors was measured. A comparison between the particle and wire-like structure sensors revealed that the latter have numerous advantages in terms of reliability and high sensitivity. Although its high surface-to-volume ratio, the nanoparticle sensor exhibited the lowest sensitivity. The high surface-to-volume ratio and low density of grain boundaries is the best way to improve the sensitivity of SnO2 gas sensors, as in case of nanowire sensor which exhibited a dramatic improvement in sensitivity to NO2 gas. 相似文献
3.
In our earlier study, we reported that at 300 °C, a 2.0 wt.% CeO2-doped SnO2 sensor is highly selective to ethanol in the presence of CO and CH4 gases [F. Pourfayaz, A. Khodadadi, Y. Mortazavi, S.S. Mohajerzadeh, CeO2 doped SnO2 sensor selective to ethanol in presence of CO, LPG and CH4, Sens. Actuators B 108 (2005) 172–176]. In the present investigation, we report the influence of ambient air humidity on the ethanol selective SnO2 sensor doped with 2.0 wt.% CeO2. Maximum response to ethanol occurs at 300 °C which decreases with the relative humidity. The relative humidity was changed from 0 to 80% for different ambient air temperatures of 30, 40 and 50 °C and the response of the sensor was monitored in a 250–450 °C temperature range. As the relative humidity in 50 °C air increased from 0 to 30%, a 15% reduction in the maximum response to ethanol was observed. A further increase in the relative humidity no longer reduced the response significantly. The presence of humidity improved the sensor response to both CO and CH4 up to 350 °C after which the extent of improvement became smaller and at 450 °C was almost diminished. The sensor is shown to be quite selective to ethanol in the presence of humid air containing CO and CH4. The selectivity passes a maximum at 300 °C; however it declines at higher operating temperatures. 相似文献
4.
A highly sensitive and fast responding CO sensor was fabricated from a sheet-like SnO2. The SnO sheets were prepared by a room temperature reaction between SnCl2, hydrazine and NaOH, and they were subsequently oxidized into SnO2 sheets at high temperature (600 °C). The morphology and size of the SnO2 sheets could be controlled during the formation of SnO, which influence the sensor response (Ra/Rg) and response time to a great extent. The sensor response of SnO nanosheets to 10 ppm CO was enhanced up to 2.34, and the 90% sensor response time could be reduced to 6 s, which are significantly higher and shorter than those of SnO2 powders (1.57 and 88 s), respectively. The realization of both a high sensitivity and rapid response were explained in terms of rapid gas diffusion onto the entire sensing surface due to the less-agglomerated and very thin structure of SnO2 nanosheets and the catalytic effect of Pt. 相似文献
5.
Divya HaridasAuthor VitaeArijit ChowdhuriAuthor Vitae K. SreenivasAuthor VitaeVinay GuptaAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(1):89-95
This paper reports the sensing response characteristics of rf-sputtered SnO2 thin films (90 nm thick) loaded with platinum catalyst cluster of varying thickness (2-20 nm) for LPG detection. The enhanced response (5 × 103) was obtained for 200 ppm LPG with the presence of 10 nm thin and uniformly distributed Pt catalyst clusters on the surface of SnO2 thin film at a relatively low operating temperature (220 °C). The high response for LPG is shown to be primarily due to the enhanced catalytic activity for adsorbed oxygen on the surface of SnO2 thin film besides the spill over mechanism at elevated temperature. 相似文献
6.
The conductance of several tin oxide gas sensitive layers was simultaneously measured in thermo-cyclic and isothermal operation mode at various concentrations of CO and propene in air, respectively. Different measurement conditions were set by the cycle time, the gas flow rate, the humidity and the thickness of the sensitive layer. The sensor response is expressed by the conductance-over-time profiles (CTPs), the gas sensitivity or by the sum of the CTP sampling points. The resultant sensitivities from the CTPs were found to be higher than those of the isothermal measurements. The CTPs considerably change with the kind of gas as well as with the variation of the measurement conditions. This is discussed for both types of target gases with respect to the temperature, the adsorbates assumed and the reaction kinetics in relation to the gas transport conditions in the porous gas sensitive layer. 相似文献
7.
Divya HaridasAuthor Vitae Arijit ChowdhuriAuthor VitaeK. SreenivasAuthor Vitae Vinay GuptaAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(1):152-157
The room temperature response characteristics of SnO2 thin film sensor loaded with platinum catalyst clusters are investigated for LPG under the exposure of ultraviolet radiation. The SnO2-Pt cluster sensor structures have been prepared using rf sputtering. Combined effect of UV radiation exposure (λ = 365 nm) and presence of Pt catalyst clusters (10 nm thick) on SnO2 thin film sensor surface is seen to lead to an enhanced response (4.4 × 103) for the detection of LPG (200 ppm) at room temperature whereas in the absence of UV illumination a comparable response (∼5 × 103) could be obtained but only at an elevated temperature of 220 °C. The present study therefore investigates the effect of UV illumination on LPG sensing characteristics of SnO2 sensors loaded with Pt clusters of varying thickness values. Results indicate the possibility of utilizing the sensor structure with novel dispersal of Pt catalyst clusters on SnO2 film surface for efficient detection of LPG at room temperature under the illumination of UV radiations. 相似文献
8.
Pengcheng Zhixuan Qingyi Jiaqiang Qun Weijun Yuliang 《Sensors and actuators. B, Chemical》2008,130(2):802-808
Flexural In2O3 nanowires with high aspect ratios were synthesized via a hydrothermal–annealing route. The as-synthesized In2O3 nanowires had diameters of 30–50 nm and length up to several microns. Various reaction parameters, such as the kind of reagents, the time of hydrothermal treatment, annealing time and annealing temperature, were investigated by a series of control experiments. The as-synthesized In2O3 nanowires showed excellent gas-sensing properties to NO2 in terms of sensor response and selectivity. 相似文献
9.
R.B Vasiliev M.N Rumyantseva N.V Yakovlev A.M Gaskov Author vitae 《Sensors and actuators. B, Chemical》1998,50(3):186-193
CuO/SnO2 heterostructures as well as SnO2(CuO) polycrystalline films have been studied for H2S sensing. Gas sensing properties of these materials have been compared in conditions: 25–300 ppm H2S in N2 at 100–250°C. A shorter response time of the heterostructures as compared to that of the SnO2(CuO) films has been found. It is suggested that the improvement of dynamic sensor properties of SnO2/CuO heterostructures is caused by the localization of electrical barrier between CuO and SnO2 layers. 相似文献
10.
In the present study nanocrystalline pristine and Pd-doped SnO2 (Pd:SnO2) with various mol% Pd have been synthesized by a modified Pechini citrate route. Transmission electron microscopy and X-ray powder diffraction studies were used to characterize the morphology, crystallinity, and structure of the SnO2 and Pd:SnO2. The response of the pristine SnO2 and Pd:SnO2 was studied towards different reducing gases. The 1.5 mol% Pd doping showed an enhanced response of 75 and 95% towards LPG at as low as 50 and 100 °C, respectively, which were quite large high value as compared with pristine SnO2 (38 and 35% at 50 and 100 °C, respectively). Structural characterization revealed that Pd doping reduced the crystallite size of SnO2 and helps in the formation of distinct spherical nanospheres at a calcinations temperature of 500 °C. Thus the increase in LPG response can be correlated with the spherical morphology, a decrease in the crystallite size (11 nm) due to doping with Pd as compared with the pristine SnO2 (26 nm) and main role of Pd as a catalyst. 相似文献
11.
Hiroyuki YamauraAuthor VitaeYuji IwasakiAuthor Vitae Shinsuke HiraoAuthor VitaeHidenori YahiroAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(2):465-467
The CO sensing property of CuO-loaded SnO2-In2O3 sensor was investigated in a reducing atmosphere. The sensor response to CO for CuO/SnO2-In2O3 (8/2) was much higher than that for CuO/SnO2 in the range of 200-1000 ppm of CO concentration. Such a high sensor response of CuO/SnO2-In2O3 may originate from the high dispersion of CuO playing a role as sensing site. 相似文献
12.
Mesoporous SnO2 is obtained through a simple hydrothermal process by using tin chloride as a raw material, urea as a pore-forming agent and pH regulator. X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) nitrogen adsorption–desorption measurements are employed to characterize the obtained mesoporous structures. The results show that the as synthesized material after calcination can be well indexed to tetragonal phase SnO2 with a mesoporous structure. The sensing properties of the sensor based on mesoporous SnO2 are investigated. The results reveal that the response to dilute Cl2 gas of the materials is very high and fast. The short recovery time mainly attributes to the bigger pore size of mesoporous SnO2. Finally, the reaction mechanism is proposed. 相似文献
13.
Jing Zhao Weinan Wang Yinping Liu Jinming Ma Xiaowei Li Yu Du Geyu Lu Author vitae 《Sensors and actuators. B, Chemical》2011,160(1):604
Ordered mesoporous SnO2 and mesoporous Pd/SnO2 have been successfully synthesized via nanocasting method using the hexagonal mesoporous SBA-15 as template. Two different procedures, impregnation technique and direct synthesis, were utilized for the doping of Pd in the mesoporous SnO2. The results of small angle X-ray diffraction (SAXD), nitrogen adsorption–desorption and transmission electron microscopy (TEM) demonstrate that the SnO2 and Pd/SnO2 display ordered mesoporous structures and high surface areas. Wide angle X-ray diffraction (WAXD) and X-ray photoelectron spectroscopy (XPS) reveal tetragonal structure of SnO2 and the existence of Pd element. The sensing properties of mesoporous SnO2 and mesoporous Pd/SnO2 for H2 were detected. The sensor utilizing mesoporous Pd/SnO2 via direct synthesis method exhibits excellent response and recovery behavior and much higher sensitivity to H2, compared to those using mesoporous SnO2 and mesoporous Pd/SnO2 via impregnation technique. It is believed that its high gas sensing performance is derived from the large surface area, high activity and well dispersion of Pd additive, as well as high porosity, which lead to highly effective surface interaction between the target gas molecules and the surface active sites. 相似文献
14.
This paper presents the ability of electrostatic sprayed tin oxide (SnO2) and tin oxide doped with copper oxide (1, 2, and 4 at.% Cu) films to detect different pollutant gases, i.e., H2S, SO2, and NO2. The influence of a copper oxide dopant on the SnO2 morphology is studied using scanning electron microscopy (SEM) technique, which reveals a small decrease in the porosity and particle size when the amount of dopant is increased. The sensing properties of the SnO2 films are greatly improved by doping, i.e., the Cu-doped SnO2 films have large response to low concentration (10 ppm) of H2S at low operating temperature (100 °C). Furthermore, no cross-sensitivity to 1 ppm NO2 and 20 ppm SO2 is observed. Among the studied films, the 1 at.% Cu-doped SnO2 layer is the most sensitive in the detection of all the studied gases. 相似文献
15.
Peng SunAuthor VitaeYanfeng SunAuthor Vitae Jian MaAuthor VitaeLu YouAuthor Vitae Geyu LuAuthor Vitae Wuyou FuAuthor VitaeMinghui LiAuthor Vitae Haibin YangAuthor Vitae 《Sensors and actuators. B, Chemical》2011,155(2):606-611
Large-scale novel core-shell structural SnO2/ZnSnO3 microspheres were successfully synthesized by a simple hydrothermal method with the help of the surfactant poly(vinyl pyrrolidone) PVP. The as-synthesized samples were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The results indicate that the shell was formed by single crystalline ZnSnO3 nanorods and the core was formed by aggregated SnO2 nanoparticles. The effects of PVP and hydrothermal time on the morphology of SnO2/ZnSnO3 were investigated. A possible formation mechanism of these hierarchical structures was discussed. Moreover, the sensor performance of the prepared core-shell SnO2/ZnSnO3 nanostructures to ethanol was studied. The results indicate that the as-synthesized samples exhibited high response and quick response-recovery to ethanol. 相似文献
16.
Yangong ZhengAuthor VitaeJing WangAuthor Vitae Pengjun YaoAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(2):723-730
Formaldehyde is a kind of hazardous gases dangerous to human health. Hence, gas sensor is an essential device to monitor formaldehyde in air, especially in indoor ambient. Semiconductor metal oxides are studied as gas-sensing material to detect most of key gases for decade years. For the purpose of actual application and meeting a variety of conditions, diverse additives added into host material are expected to improve the performance of gas sensors. The formaldehyde gas-sensing characteristics of undoped and NiO-doped SnO2 (NSO) nanofibers synthesized via a simple electrospinning method were investigated in this study. It is noticed that the addition of NiO causes the distortion at the surface of SnO2 nanofibers, which is responsible to adjust activation energy, grain sizes and chemical states of host material. The sensors fabricated from NSO nanofibers exhibited good formaldehyde sensing properties at operating temperature 200 °C, and the minimum-detection-limit was down to 0.08 ppm. The response time and recovery time of the sensors were about 50 s and 80 s to 10 ppm formaldehyde, respectively. The sensor shows a good long-term stability in 90 days. The simple preparation and excellent properties significantly advance the viability of electrospun nanofibers as gas sensing materials. The sensing mechanisms of NSO nanofibers to formaldehyde were discussed. The results indicated that NSO nanofibers could be used as a candidate to fabricate formaldehyde sensors in practice. 相似文献
17.
Audrey ChapelleAuthor Vitae Mohd H. YaacobAuthor Vitae Isabelle PasquetAuthor VitaeLionel PresmanesAuthor Vitae Antoine BarnabéAuthor VitaePhilippe TailhadesAuthor Vitae Johan Du PlessisAuthor VitaeKourosh Kalantar-zadehAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(1):117-124
Nanocrystalline CuO-CuxFe3−xO4 thin films were developed using a radio-frequency sputtering method followed by a thermal oxidation process. Thin films were deposited applying two very different conditions by varying the argon pressure and the target-to-substrate distance. Structural, microstructural and gas-sensing characteristics were performed using grazing incidence X-ray diffraction (GXRD), Raman spectroscopy, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and electrical measurements. Their sensing properties were examined using hydrogen gas in dry synthetic air. The shortest response and recovery times were observed between 280 and 300 °C independently of the deposition conditions. 相似文献
18.
Lijun GuoAuthor VitaeXiaoping ShenAuthor Vitae Guoxing ZhuAuthor VitaeKangmin ChenAuthor Vitae 《Sensors and actuators. B, Chemical》2011,155(2):752-758
In2O3 porous nanoplatelets were successfully synthesized by solvothermal treatment of indium acetylacetonate, followed by calcination in air. X-ray diffraction and Raman spectrum measurements demonstrate that the products are pure cubic phase In2O3. Scanning electron microscopy and transmission electron microscopy analyses reveal that the In2O3 nanoplatelets bounded by {1 1 0} planes with thickness less than 6 nm and length about 20-50 nm are single crystalline but with porous structure. The optical absorption property of the In2O3 nanoplatelets was investigated by UV-vis spectroscopy, which indicates that the In2O3 nanoplatelets are semiconducting with a direct band gap of 3.1 eV. The gas sensing performance of the as-prepared In2O3 porous nanoplatelets was investigated towards a series of typical organic solvents and fuels. It was found that the In2O3 porous nanoplatelets show structure-induced enhancement of gas sensing performance, and especially possess high sensitivity and rapid response towards ethanol vapor. 相似文献
19.
Huitao FanAuthor VitaeYi ZengAuthor Vitae Xiujuan XuAuthor VitaeNing LvAuthor Vitae Tong ZhangAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(1):170-175
Hollow ZnSnO3 microspheres were successfully prepared by hydrothermal method at 160 °C for 12 h. The prepared material was characterized by field emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and X-ray diffraction measurements (XRD). The average diameter of the hollow ZnSnO3 microspheres was in the range of 400-600 nm. Compared with solid ZnSnO3 microspheres structure, the hollow ZnSnO3 microspheres showed better response (S) to butane. To 500 ppm butane, the sensor response (S) of the hollow ZnSnO3 microspheres was 5.79 at the optimum operating temperature of 380 °C, and the response and recovery time were 0.3 s and 0.65 s, respectively. The sensitivities of sensors based on this material were linear with the concentration of butane in the range of 100-1000 ppm. 相似文献
20.
Lina Yingqiang Xueliang Shurong Shoumin Shihua 《Sensors and actuators. B, Chemical》2007,120(2):568-572
A polyaniline (PAni)/SnO2 hybrid material was prepared by a hydrothermal method and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The XRD pattern suggested that PAni did not modify the crystal structure of SnO2, but SnO2 affected the crystallization of PAni to some extent. The gas sensitivity of the PAni/SnO2 hybrid was also studied to ethanol and acetone at operation temperatures of 30, 60 and 90 °C. It was found that the PAni/SnO2 hybrid material had gas sensitivity only when operated at 60 and 90 °C, and it showed a linear relationship between the responses and the concentrations of ethanol and acetone at 90 °C. The sensing mechanism was also discussed. 相似文献